Electric current sensor

Abstract

An electric current sensor includes first, second, and third current sensor modules, each including at least one bus bar formed in a rectangular shape extending in a width direction in cross section, to carry an electric current along a length direction perpendicular to the width direction, one pair of shield plates made of a magnetic material and disposed in a height direction perpendicular to the width direction and the length direction in such a manner as to sandwich the at least one bus bar therebetween, and at least one magnetic detection element disposed between the at least one bus bar and one of the one pair of shield plates, to detect a strength of a magnetic field in the width direction. The first, the second, and the third current sensor modules are arranged by superposition on top of each other in the height direction.

What is claimed is: 
     
         1 . An electric current sensor, comprising:
 first, second, and third electric current sensor modules, each including at least one bus bar formed in a rectangular shape extending in a width direction in cross section, to carry an electric current along a length direction perpendicular to the width direction, one pair of shield plates made of a magnetic material and disposed in a height direction perpendicular to the width direction and the length direction in such a manner as to sandwich the at least one bus bar therebetween, and at least one magnetic detection element disposed between the at least one bus bar and one of the one pair of shield plates, to detect a strength of a magnetic field in the width direction,   wherein the first, the second, and the third electric current sensor modules are arranged by superposition on top of each other in the height direction.   
     
     
         2 . The electric current sensor according to  claim 1 , wherein the first and the second electric current sensor modules each include three bus bars and three magnetic detection elements. 
     
     
         3 . The electric current sensor according to  claim 2 , wherein the third electric current sensor module includes one bus bar and one magnetic detection element. 
     
     
         4 . The electric current sensor according to  claim 2 , wherein the three magnetic detection elements included in the first electric current sensor module and the three magnetic detection elements included in the second electric current sensor module are arranged in the same locations in the width direction. 
     
     
         5 . The electric current sensor according to  claim 4 , wherein the one magnetic detection element included in the third electric current sensor module is arranged in the same location in the width direction as the magnetic detection elements located in a middle in the width direction, of the three magnetic detection elements included in the first electric current sensor module and the three magnetic detection elements included in the second electric current sensor module. 
     
     
         6 . The electric current sensor according to  claim 1 , wherein the magnetic detection elements included in the first, the second, and the third electric current sensor modules are arranged halfway in the height direction between the one pair of shield plates of the first, the second, and the third electric current sensor modules, respectively. 
     
     
         7 . The electric current sensor according to  claim 1 , wherein the one pairs of shield plates included in the first, the second, and the third electric current sensor modules are the same in size. 
     
     
         8 . The electric current sensor according to  claim 1 , wherein at least one of the first, the second, and the third electric current sensor modules is being provided with an electrical conducting body made of a nonmagnetic electrical conducting material tween the at least one magnetic detection element thereof and one of the one pair of shield plates thereof. 
     
     
         9 . The electric current sensor according to  claim 1 , further comprising:
 additional shield plates, which, with the first, the second, and the third electric current sensor modules being arranged by superposition on top of each other in the height direction, are being provided on a lower side of a lowermost shield plate and an upper side of an uppermost shield plate, respectively, located in the first, the second, and the third electric current sensor modules.   
     
     
         10 . The electric current sensor according to  claim 1 , further comprising:
 at least one electric current sensor module, which is arranged by superposition on top of the first, the second, and the third electric current sensor modules, in addition to the first, the second, and the third electric current sensor modules.